After his fourth combat tour, to Afghanistan in 2011, Sgt. 1st Class Michael B. Lube, a proud member of the Army Special Forces, came home alienated and angry. Once a rock-solid sergeant and devoted husband, he became sullen, took to drinking, got in trouble with his commanders and started beating his wife.

"He would put this mask on, but behind it was a shattered version of the man I knew," his wife, Susan Ullman, said. She begged him to get help, but he refused, telling her: "I'll lose my security clearance. I'll get thrown out." When she quietly reached out to his superior officers for guidance, she said, she was told: "Keep it in the family. Deal with it."

And so he did. Last summer, just days after his 36th birthday, Lube put on his Green Beret uniform and scribbled a note, saying, "I'm so goddamn tired of holding it together." Then he placed a gun to his head and pulled the trigger.

To a growing number of medical experts and the Special Operations Command itself, suicides by soldiers like Lube tell a troubling story about the toll of war on the nation's elite troops. For 12 long years, those forces, working mostly in secret, carried the burden of much front-line combat, deploying time and again to the most violent sectors of Iraq and Afghanistan.

Yet for all their well-known resilience, an emerging body of research suggests that Special Operations forces have experienced, often in silence, significant traumatic brain injury and post-traumatic stress disorder. Both conditions have been linked in research to depression and, sometimes, suicidal behavior.

Absent other data, suicide has emerged as the clearest indicator of the problem: In the past 2 1/2 years, 49 Special Operations members have killed themselves, more than in the preceding five years. While suicides for the rest of the active-duty military have started to decline, after years of steady increases, they have risen for the nation's commandos.

High-stress work

"The numbers are shocking," said Dr. Geoffrey Ling, a leading brain-trauma expert and director of biological technologies at the Defense Advanced Research Projects Agency. He believes Special Operations forces are at higher risk of traumatic brain injury and post-traumatic stress because of their high-stress work, he said. "To us, it is a canary telling us there are bigger problems at hand."

The highest levels of the command have taken notice. With Special Operations forces expected to continue deploying not only to Afghanistan, but also to hot spots like North Africa and Southeast Asia for years to come, senior commanders are openly pushing their troops to seek help and worrying that the struggle to heal the force has only begun.

Adm. William H. McRaven, who oversaw the Navy SEAL raid that killed Osama bin Laden and who now heads the Special Operations Command, has created a task force, Preservation of the Force and Family, to address the mental, emotional and physical needs of his troops. In a 12-page internal document disseminated in late March, he ordered new procedures and training to "help leaders at all levels do everything we can to prevent a suicide."

"My soldiers have been fighting now for 12, 13 years in hard combat - hard combat - and anybody that has spent any time in this war has been changed by it," McRaven said in a recent speech. "I don't think we'll see that begin to manifest itself for another year or so. Maybe two, three years."

Congress has also gotten involved. The House Armed Services Committee, noting the suicide rate, recently voted to shift $23 million to therapies for brain injury, post-traumatic stress disorder and suicide prevention for Special Operations forces.

Despite the growing problem, a serious obstacle remains to fixing it: the culture of Special Operations itself. Even more than conventional forces, commandos have been taught to fight through injury and remain stoic about pain, whether physical or psychological. Breaking through that resistance to seek help may prove to be among the greatest challenges facing the commanders.

"We obviously have a peer-to-peer stigma, the machismo that 'I can't admit that I have to see a counselor or psychiatrist, that makes me weak and we're at war, and there can't be any chinks in the armor,' " said Command Sgt. Maj. Chris Faris, an 18-year veteran of Delta Force, the top-secret Army counterterrorism unit.

For Faris, now the Special Operations Command's senior enlisted adviser, several years passed before he realized how war had scarred him on the inside. Early in his long Special Operations career, he was part of the task force that tried to wrest Somalia from warlords in 1993; he was wounded and saw numerous colleagues killed during the calamitous battle made famous by the film "Black Hawk Down." When he moved with McRaven in 2011 to the command's headquarters in Tampa, Fla., alarm about the condition of their battered force was already rising. On their desks was a sobering new report commissioned by the departing commander, Adm. Eric T. Olson, which described a fraying force and troubling rates of broken marriages, alcoholism and other concerns. As they began mapping out policies, McRaven realized that his longtime aide was suffering from some of the same problems.

To his recollection, he had been wounded only once by an explosion: two decades earlier, in Mogadishu, Somalia, possibly by a rocket-propelled grenade. Doctors, however, told him that he had four spots on his brain and that he had traumatic brain injury. Faris said there was no scientific way to know how his brain injury had occurred, but he theorized that it stemmed from years of training with explosive charges to blow down doors and walls, a tactic known as breaching. He estimated he had been exposed to thousands of breaching charges.

A growing number of longtime commandos and researchers have reached similar conclusions. While far smaller than roadside bombs, the low-level blasts used in breaching - which troops endure many times over years of deployments and training, often with little time to recover - may cause cumulative and significant damage to the brain, experts say.

Other tactics common among some Special Operations forces - including the firing of recoilless rifles and other heavy weapons - may have similar long-term effects.

In 2008, military researchers from the United States, New Zealand and Canada independently reported accounts of a collection of symptoms from people routinely exposed to low-level blasts that included fatigue, memory difficulties, headaches and slowed thought processes. "Breacher's brain," it was called. And last year, the findings of a study of New Zealand soldiers suggested "a measurable degree of brain perturbation" from exposure to breaching blasts in training.

'I have nothing left'

For Lube, the demons were just taking hold after he returned from Afghanistan three years ago, when these initiatives to destigmatize mental health care were not widespread across Special Operations his widow, Ullman, said.

Then, last summer, he called Ullman with bad news. The infractions had mounted, bringing the ultimate professional indignity: He was to be dishonorably discharged. "He said: 'I can't struggle anymore. I have nothing left,' " Ullman recalled.

Then he told her: "You know, baby, this is a lot harder to do than it looks like on TV. I'll always love you."

And, she said, "that was it."

Without thinking through what she wanted to accomplish, she just started calling members of Congress. "I would say: 'Here is Michael's story. I know he's not the only one. Perhaps members of your constituency have gone through it, too,'" she said.

Lawmakers embraced her efforts.

Ullman received the Army's official 100-page inquiry report, which included the grim police photographs of the suicide. Since his death, she had often caught herself daydreaming that he was simply away on another overseas mission. The photographs, though horrific, made her confront the reality.